In recent years, techniques for controlling the surface scattering of printed images have been developed, and there has been a trend of using digital techniques to reproduce a print object with an elaborate design by matching colors and reflective properties with those of the inputted original. PTL 1 describes the following. Specifically, a method is described in which: from a subject placed and illuminated on a planar base, diffuse reflection image signals and gloss signals, which indicate the degree of gloss, are obtained desirably in two directions, namely, a main-scanning direction and a sub-scanning direction; and after the diffuse reflection image signals are outputted with color inks, a shape is formed with a transparent ink to reproduce the gloss of the gloss signals in the two directions.
Also, according to a technique described in NPL 1, it is possible to reproduce anisotropic reflection in which, like satin or the like, the intensity of gloss and the shading change with changes in the incident direction of light and the viewing direction. Note that, in the print reproduction in NPL 1, a three-dimensional printer is used, and concavities and convexities are provided on the surface to allow surface scattering to change depending on the incident angle and the viewing angle.